645297123 has 4 divisors (see below), whose sum is σ = 860396168. Its totient is φ = 430198080.

The previous prime is 645297091. The next prime is 645297179. The reversal of 645297123 is 321792546.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 645297123 - 2⁵ = 645297091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645297823) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107549518 + ... + 107549523.

It is an arithmetic number, because the mean of its divisors is an integer number (215099042).

Almost surely, 2^645297123 is an apocalyptic number.

645297123 is a deficient number, since it is larger than the sum of its proper divisors (215099045).

645297123 is a wasteful number, since it uses less digits than its factorization.

645297123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215099044.

The product of its digits is 90720, while the sum is 39.

The square root of 645297123 is about 25402.6991282423. The cubic root of 645297123 is about 864.1449101615.

The spelling of 645297123 in words is "six hundred forty-five million, two hundred ninety-seven thousand, one hundred twenty-three".